The Indian legends mention a bridge built between the tip of South India and the island of Sri Lanka around 1,750,000 Years ago known as Ram Setu.
Here’s and interesting twist on this bridge – the bridge appears in one of Nasa’s pictures and NASA calls it Adam’s bridge. NASA believes it to be of natural formation.
The Indian Government is working on a project called Setu Samudram shipping canal project (SSCP). This will actually cut through this rock formation to create a shipping canal, which will eventually save about 400 nautical miles in the voyage around Sri Lanka. But as you can imagine there is a lot of opposition to this project from religious groups.
Also, according to this article, this bridge prevented the 2004 tsunami from reaching the eastern coast of India.